 U.S. Department of Transportation Federal Highway Administration |
MEMORANDUM |
| Subject: | Information: Dunn Memorial Bridge Structural Investigation | Date: | December 6, 2005 |
| From: | M. Myint Lwin, P.E., S.E. Director, Office of Bridge Technology |
Reply to: Attn. of: |
HNG-30 |
| To: | Director of Field Services Resource Center Director and Operations Managers Division Administrators Federal Lands Highway Division Engineers |
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This memorandum advises you of an incident in New York State regarding a span that failed as a result of a tipped-over rocker bearing on a flyover ramp in the Interstate 787 Dunn Memorial Bridge interchange complex in downtown Albany, New York. The failure happened on July 27, 2005.
A Forensic Investigation report was prepared and released by the New York State Department of Transportation (NYSDOT) on October 21, 2005. The NYSDOT also issued a Technical Advisory, which provides new inspection and monitoring requirements for high rocker bearings. It was issued on October 4, 2005, to all State and consultant personnel currently involved in the bridge inspection program.
Both documents are available at the following pages on the State's web site for your use. The Forensic Report and its Appendices are listed as two separate items on page http://www.dot.state.ny.us/structures/manuals.html The Technical Advisory is listed as the last appendix on page http://www.dot.state.ny.us/structures/manuals/man_inspection.html
The NYSDOT began the forensic evaluation immediately after the event and consulted with FHWA engineers from the Office of Bridge Technology and the Division Office. The findings show that the failure was a result of excessive horizontal deflection of a bridge pier that was caused by a combination of factors that included overextension and improper function of the high rocker bearings as well as the flexural properties of the pier inherent in its original design. Temperature fluctuations, traffic loads, or a combination of these conditions likely triggered the chain of events that led to loss of support of the span.
For the safety of the traveling public, please advise your State of the New York experience to ensure that bridges with similar bearings and conditions are receiving appropriate inspection and/or monitoring.
If you have any questions please call Benjamin Tang at (202) 366-4592, or Daniel Byer at (518) 431-4125, extension 253. Also, George Christian, Director, Technical Resource Center, or his assistant Arthur Yannotti, both at NYSDOT, may be contacted directly at (518) 457-6827.
cc:
Dan Byer HBR-NY
George Christian NYSDOT